References of "Vandewalle, Nicolas"
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See detailCustomizing mesoscale self-assembly with three-dimensional printing
Poty, Martin ULg; Lumay, Geoffroy ULg; Vandewalle, Nicolas ULg

in New Journal of Physics (2014)

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See detailMicrofluidic on optical fibers: Towards a new kind of fluorescent biosensor
Lismont, Marjorie ULg; Vandewalle, Nicolas ULg; Weyer, Floriane ULg et al

Poster (2014, February)

In recent works, the behavior of droplets moving along vertical treads due to gravity was studied. It appeared that the droplet can be stopped by encountering a horizontal fiber depending on droplet ... [more ▼]

In recent works, the behavior of droplets moving along vertical treads due to gravity was studied. It appeared that the droplet can be stopped by encountering a horizontal fiber depending on droplet volumes and fiber characteristics. On the basis of this behavior and by replacing treads by two crossed optical fibers, it is possible to combine fluidics and optics to develop a new kind of fluorescent sensor. In our work, the intersection between two crossed optical fibers is used as the basic unit of an original optofluidic biosensor. These two optical fibers are used as droplets carriers: one for probe molecules and the other one for target species. The fiber's junction catches the droplets and act as a reaction center. The main advantage of using optical fibers resides in their ability to propagate and collect light to and from the droplet localized at the fiber's crossing. This optical fiber configuration can therefore allow the study of biological interactions using fluorescent labels. This new and versatile detection scheme was validated on a calcium indicator where ions detection is accomplished by using a dye, Oregon green Bapta-2, that has a Ca 2+ recognition group as well as an entity exhibiting fluorescence. A FRET recognition event, between Rh-Con A and FITC-Dextran, was also investigated to detect glucose. Finally, a prototype of a multiplexing device, composed of several juxtaposed fibers' junctions, was developed. [less ▲]

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See detailNonlinear Schrödinger wave equation with linear quantum behavior
Richardson, Christopher ULg; Schlagheck, Peter ULg; Martin, John ULg et al

in Physical Review. A (2014), 89

We show that a nonlinear Schro ̈dinger wave equation can reproduce all the features of linear quantum mechanics. This nonlinear wave equation is obtained by exploring, in a uniform language, the ... [more ▼]

We show that a nonlinear Schro ̈dinger wave equation can reproduce all the features of linear quantum mechanics. This nonlinear wave equation is obtained by exploring, in a uniform language, the transition from fully classical theory governed by a nonlinear classical wave equation to quantum theory. The classical wave equation includes a nonlinear classicality enforcing potential which when eliminated transforms the wave equation into the linear Schro ̈dinger equation. We show that it is not necessary to completely cancel this nonlinearity to recover the linear behavior of quantum mechanics. Scaling the classicality enforcing potential is sufficient to have quantumlike features appear and is equivalent to scaling Planck’s constant. [less ▲]

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See detailMagnetic ghosts and monopoles
Vandewalle, Nicolas ULg; Dorbolo, Stéphane ULg

in New Journal of Physics (2014), 16

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See detailBouncing dynamics of a spring
Hubert, Maxime ULg; Ludewig, François ULg; Dorbolo, Stéphane ULg et al

in Physica D: Nonlinear Phenomena (2014), 272

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See detailSuccessive Droplets Encapsulation Revealed by Optofluidics
Lismont, Marjorie ULg; Robert, Damien; Vandewalle, Nicolas ULg et al

Poster (2013, November)

Digital microfluidics: an easy way to encapsulate successively water droplets by oil. Digital microfluidics is implemented to coat successively water droplets with a thin layer of silicon oil. Small water ... [more ▼]

Digital microfluidics: an easy way to encapsulate successively water droplets by oil. Digital microfluidics is implemented to coat successively water droplets with a thin layer of silicon oil. Small water droplets are settled at three fibers nodes while a larger oil drop slides down the vertical fiber. Optofluidics: an interesting way to reveal the droplet sliding motion and the encapsulation. To distinguish the different fluids, quantum dots (QDs) and rhodamine labelled polystyrene beads are diluted in oil and water, respectively.These two fluorescent probes are lighted by a 532 nm radiation.The fluorescence signal is recorded by a high speed camera, perpendicularly to the laser and to the fibers network. This set-up reveals that the oil drop passes through the water droplets without removing them from the nodes, leaving a thin oil layer around the water droplets. The coating, clearly seen on top pictures of Fig 2, prevents water evaporation. The key parameters for a good encapsulation are the fiber diameter and the oil viscosity that determine droplets size and velocity, respectively. [less ▲]

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See detailEncapsulation of water droplets on fibers
Weyer, Floriane ULg; Dreesen, Laurent ULg; Vandewalle, Nicolas ULg

Poster (2013, November)

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See detailHow dynamical clustering triggers Maxwell's demon in microgravity
Opsomer, Eric ULg; Noirhomme, Martial ULg; Vandewalle, Nicolas ULg et al

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2013), 88

In microgravity, the gathering of granular material can be achieved by a dynamical clustering whose existence depends on the geometry of the cell that contains the particles and the energy that is ... [more ▼]

In microgravity, the gathering of granular material can be achieved by a dynamical clustering whose existence depends on the geometry of the cell that contains the particles and the energy that is injected into the system. By compartmentalizing the cell in several subcells of smaller volume, local clustering is triggered and the so formed dense regions act as stable traps. In this paper, molecular dynamics simulations were performed in order to reproduce the phenomenon and to analyze the formation and the stability of such traps. Depending on the total number N of particles present in the whole system, several clustering modes are encountered and a corresponding bifurcation diagram is presented. Moreover, an iterative model based on the measured particle flux F as well as a theoretical model giving the asymptotical steady states are used to validate our results. The obtained results are promising and can provide ways to manipulate grains in microgravity. [less ▲]

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See detailMelting of a confined monolayer of magnetized beads
Schockmel, Julien ULg; Mersch, Eric; Vandewalle, Nicolas ULg et al

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2013)

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See detailDynamiques complexes de rebonds d'une goutte placée sur un bain vibré: résonances et anti-résonances
Hubert, Maxime ULg; Vandewalle, Nicolas ULg

in Hubert, Maxime; Vandewalle, Nicolas (Eds.) Comptes-rendus de la 16e Rencontre du Non-linéaire Paris 2013 (2013, March 25)

We present herebelow a model for bouncing droplets consisting of two masses joined by a spring and a damper bouncing onto an oscillating plate. We analyze the dynamics through the bouncing threshold and ... [more ▼]

We present herebelow a model for bouncing droplets consisting of two masses joined by a spring and a damper bouncing onto an oscillating plate. We analyze the dynamics through the bouncing threshold and spatio-temporal diagrams. We obtain an analytic expression for the threshold. Resonance and Anti-resonance phenomena are found and investigated. The behavior of the bouncing spring is compared to the bouncing droplet dynamics. In particular, key features of the bouncing droplet dynamics are reproduced. [less ▲]

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See detailFlow abilities of powders and granular materials evidenced from dynamical tap density measurement
Traina, Karl; Cloots, Rudi ULg; Bontempi, Sébastien ULg et al

in Powder Technology (2013), 235

This paper offers an overview of the flow properties of granular systems, including voids, granular porosity and random packing characteristics. For the purposes of the study, the notion of additional ... [more ▼]

This paper offers an overview of the flow properties of granular systems, including voids, granular porosity and random packing characteristics. For the purposes of the study, the notion of additional porous volume is intro-duced. This volume is defined as the additional air volume added to the optimal granular packing. It represents the difference between the volume of the bulk powder bed and that of the same powder but when ideally packed. It appears as the volume of additional air (or voids) trapped/stored between the grains when the powder passes from a dynamical state to a static state (during the filling of a container or the formation of a powder heap, for example). Therefore, if the powder bed traps air, it is then able to restore air partially or completely or not at all, depending on the intergranular cohesion level. This mechanism of the storing and releasing of air can be analysed from the measurement of compressibility curves. If the powder is non-cohesive or free flowing, it traps a small amount of air in its static state. Conversely, if the powder is cohesive, it traps more air. These data can be related to the flow properties of granular materials. Indeed, the compressibility curves obtained for gran-ular materials provide information such as additional porosity, a kinetic parameter which characterizes the com-pressibility dynamics, a granular relaxation index which predicts how far a powder is from its optimal packing state and an index which gauges the de-areation speed of the powder. Measurement of such properties provides a better understanding of the nature of granular materials. Measurements of dynamical compressibility were car-ried out on five granular materials (two different lactose powders, hydrated lime Ca(OH)2, yttrium stabilized zir-conia balls and polystyrene balls). The overall results are presented using a radar graph. The use of this tool and its advantages are discussed in relation to the measurement and characterization of powder flow properties. [less ▲]

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See detailKinematic analysis of swimming ontogeny in seabass (Dicentrarchus labrax).
Olivier, Damien ULg; Vandewalle, Nicolas ULg; Parmentier, Eric ULg et al

in Belgian Journal of Zoology (2013)

Swimming has been investigated in multiple species, but few studies consider the establishment of swimming through ontogeny. This study describes the establishment of cyclical swimming in Dicentrachus ... [more ▼]

Swimming has been investigated in multiple species, but few studies consider the establishment of swimming through ontogeny. This study describes the establishment of cyclical swimming in Dicentrachus labrax, a marine fish from cold, temperate waters. The data were compared with results from previous studies on two subtropical freshwater catfish species (Clarias gariepinus and Corydoras aeneus). The three species have different modes of locomotion during their adult stage (anguilliform, subacarangiform and carangiform). The swimming of Dicentrarchus labrax was recorded with a high-speed video camera (500 fps) from 0 to 288 hours and from 960 to 2496 hours post-hatching. Three indices, i.e. coefficient of determination (r²), coefficient of variation (CV), and Strouhal number (St), were used to investigate the establishment and efficiency of swimming. Important differences in the timing of swimming establishment were observed between the seabass and the two catfish species. The two catfish species display a sine-shape swimming mode immediately or soon after hatching, and the efficiency of movement substantially improves during the first days of life. For seabass, however, establishment of swimming is slower during the same developmental period. These differences may be related to a faster developmental rate in the catfishes that allows them to swim rapidly in an intermediate regime flow and to develop the required morphology to establish efficient movements earlier. [less ▲]

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See detailMesoscale structures from magnetocapillary self-assembly
Vandewalle, Nicolas ULg; Obara, Noriko; Lumay, Geoffroy ULg

in European Physical Journal E -- Soft Matter (2013), 36

When identical soft ferromagnetic particles are suspended at some water-air interface, capillary attraction is balanced by magnetic repulsion induced by a vertical magnetic field. By adjusting the ... [more ▼]

When identical soft ferromagnetic particles are suspended at some water-air interface, capillary attraction is balanced by magnetic repulsion induced by a vertical magnetic field. By adjusting the magnetic field strength, the equilibrium interdistance between particles can be tuned. The aim of this paper is to study the ordering of particles for large assemblies. We have found an upper size limit above which the assembly collapses due to capillary effects. Before reaching this critical number of particles, defects are always present and limit the perfect ordering expected for that system. This is due to the curvature of the interface induced by the weight of the self-assembly. [less ▲]

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See detailThe role of the droplet deformations in the bouncing droplet dynamics
Terwagne, Denis ULg; Ludewig, François ULg; Vandewalle, Nicolas ULg et al

in Physics of Fluids (2013), 25

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See detailBubble bouncing at a clean water surface
zawala, jan; Dorbolo, Stéphane ULg; Vandewalle, Nicolas ULg et al

in Physical Chemistry Chemical Physics [=PCCP] (2013), 15

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See detailCascade of granular flows for characterizing segregation
Lumay, Geoffroy ULg; Boschini, Frédéric ULg; Cloots, Rudi ULg et al

in Powder Technology (2013)

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See detailSelf-assembled magnetocapillary swimmers
Lumay, Geoffroy ULg; Obara, Noriko; Weyer, Floriane et al

in Soft Matter (2013)

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See detailInfluence of the gravity on the discharge of a silo
Dorbolo, Stéphane ULg; Maquet, Laurent ULg; Brandenbourger, Martin ULg et al

in Granular Matter (2013)

Detailed reference viewed: 60 (28 ULg)